3D ultrasound imaging of the cardiac structure and blood flow

Abstract :
    Cardiovascular diseases are still the leading cause of morbidity and mortality worldwide. Acute myocardial infarction (AMI) is a critical emergency that requires immediate reperfusion therapy. Despite significant advances in revascularization, AMI is still associated with high mortality rates and long-term complications. This highlights the importance of having diagnostic tools that can monitor myocardial perfusion, viability, and reperfusion injury in real time. Echocardiography is ideally suited for emergency care among imaging modalities due to its portability, accessibility, and non-invasive nature. However, conventional two-dimensional echocardiography is limited in its ability to capture the heart's three-dimensional architecture and hemodynamics.
    Three-dimensional (3D) echocardiography has the potential to overcome these limitations by enabling direct volumetric assessment of cardiac structure and perfusion. Ultrafast ultrasound techniques further expand these capabilities by achieving the temporal resolution necessary to capture rapid cardiac dynamics. Despite these advantages, 3D echocardiography has not achieved routine clinical use in AMI. Methodological barriers remain: while transverse oscillations (TOs) are promising for flow estimation, they are not yet capable of accurately quantifying 3D blood flow across arbitrary orientations. Similarly, backscatter tensor imaging (BTI) is practical for in-plane microstructural characterization but does not currently provide complete volumetric mapping of myocardial architecture.
    This thesis addresses these gaps by developing and validating ultrafast 3D imaging methods, with a long-term objective of imaging and monitoring AMI. First, novel 3D TOs-based frameworks are introduced to estimate flow across arbitrary orientations robustly. Second, a 3D BTI approach is developed to extend structural characterization beyond in-plane constraints and enable volumetric mapping of myocardial fiber architecture. Integrating these methods with advanced volumetric acquisitions provides methodological contributions for quantifying myocardial perfusion and tissue integrity.
    By bridging key methodological gaps in 3D echocardiography, this thesis aims to develop methods that demonstrate the feasibility and potential use of 3D ultrasound for AMI.
 

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